Radio receiving system



May 8, 1934. E. L. BRESSON RADIO RECEIVING SYSTEM Filed April 27, 1931 IN V EN TOR.

V a A ATTORNEYS.

Patented May 8, 1934 UNITED sTATEs asnro momma srs'rnu Eugene L. Bronson, Mineola, N. Y.

Application April 2'1, 1931, Serial No. 533,170

12 Claims. (01. 250-20) nected in cascade with the inductances 10' and This invention relates to radio-receiving systerns, and more particularly to apparatus for receiving radio signals over a plurality of bands of carrier-wave frequencies.

The invention has for its object generally the provision of a device for receiving radio signals -in the manner indicated, which is convenient,

economical and may be manufactured from a relatively small number of parts.

More specifically, an object is to provide efllcient apparatus for receiving radio signals, particularly radio-broadcast signals, in which a plu-;

rality of bands of carrier frequencies may be modulated to vary in frequency each throughout a predetermined range in a manner that will provide high quality and faithfulnessin reproducing the signal, and will also be highly selective.

Another object is to provide apparatus of the character described, capable of eflicient operation throughout the relatively long-wave range of present-day broadcasting stations and also throughout the range of the relatively short-wave lengths of existing short-wave broadcasting stations, with reproduction in a common translating means.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts, which will be exemplifled in the constructions hereinafter set forth and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

The figure shown is a schematic diagram illustrating a radioreceiving system constructed in accordance with the invention. a

Referring now to the drawing, 10 denotes an element for picking up or collecting energy of a radio signal, which may be of any convenient form, for example an antenna, as illustrated. In accordance with the present invention, this antenna has connected to it a plurality of inductances in parallel, each of which is in series with the ground. The inductances are illustrated respectively at 10' and 101. The energy picked up by signal is transferred selectively from the inductances 10' and 101 in parallel paths through oscillating circuits adapted to amplify and rectify the signal in a desired manner, for example by means of a plurality of oscillating circuits con- 101; these oscillating circuits containing amplifying and rectifying devices of the thermionic type,

for example electron discharge tubes having three or more electrodes.

The oscillating circuits associated with each of the inductances 10' and 101 are adapted to respond selectively to a band of carrier wave frequencies, for example the inductance at 10' may be so designed with respect to its oscillating circuits, as to transfer energy having a carrier wave frequency of the band of standard broadcast signals, and the inductance at 101 so designed as to transferselectively the energy of the band of socalled short-wave frequencies.

In carrying out the present invention, the oscillating circuits which are conventionally designated radio frequency stages, associated respectively with the inductances 10' and 101, comprise parallel paths; the subsequent stages commonly designated audio frequency stages being connected so as to be common to the two paths of amplification, whereby a single translating device, such as a loud speaker, may be employed.

The first oscillating circuit associated with the inductance 10' comprises a coilor inductance 11, inductively related to the inductance 10'. To complete the oscillating circuit, a condenser 110 is connected across the terminals of the inductance 11, a suitable amplifying device being connected in parallel therewith, for example, the four-element electron discharge tube shown generally at 20. The grid electrode 209 is connected to one side of the oscillating circuit, the cathode element 200 being connected to the other side of the oscillating circuit in the usual manner. The tube also has a plate anode 209 which is connected to one terminal of a primary 21 of a radio-frequency amplifying transformer. The fourth electrode of the tube 20 is here indicated as a screen grid 20.5 which is connected in a manner as set forth more fully hereinafter.

Any convenient source of energy for heating the cathode elements of the thermionic tubes may be employed, that shown being a conventional low voltage battery 12. Similarly any convenient source of electric potential may be employed for supplying the plate electrodes of the tubes or o'her elements with proper potentials, that shown also being a battery 13 capable of giving relatively high potentials. In order that these sources may be common sources of potentials, a conductor 14 is shown as leading from one terminal of the high I tively high resistance 16 connected thereacross, suitable elements of inductance 17 and 18 being connected in series therewith, preferably in series with conductor 14, for reasons which will more fully appear hereinafter.

A conductor 19, leads from the other pole of battery 12 and is disposed parallel to conductor 15, whereby these conductors serve as supply busses for the low potential current which heats the cathode elements of the thermionic tubes in the several stages, the heated elements of which are shown connected in parallel across .these bussea,

Across the inductance 21, is shunted a variable condenser 22. A fixed radio-frequency condenser 22a may also be connected in series with the variable condenser 22, if desired. The capacitance thus introduced enables the circuit 21-22- -22a to be tuned to any desired periodicity within a given range. From the other terminal of inductance 21 leads a conductor 23 having in series a radio frequency choke 24 and a conductor 25, to make connection with a suitable source of potential, for example, a point on resistance 16. This is conveniently accomplished by providing conductor 25 with variable tap 161) on the resistance 16 so that the plate or output circuit of tube 20 has therein a uni-directional potential of a value corresponding to portion 16b-16a of the resistance 16, the circuit being compleled by way of conductor 15 to the cathode'20c. The radio-frequency choke 24 serves to prevent radiofrequency currents from getting into the source of direct current supply: Conductor 26 connects the conductor 19 to the circuit 21, 22 and 22a at a point between the condensers, thus completing the cathode-plate radio frequency output circuit of tube 20.

The screen grid 20s is supplied with an appropriate potential to neutralize the capacity coupling between the grid and plate, thus to prevent feed-back and oscillation of the tube. Preferably, the potential applied to the screen grid 20s is predeterminable at will or adjustable to suit the particular conditions met with. This may be accomplished by providing variable tap 160 on the resistance 16, connected by a conductor 30, and series resistance 31, to the screen grid 20s. Resistance 31 is a relatively high resistance acting to prevent any tendency of the plate circuit to react upon the screen grid fromaiiecting the rest of the circuit, thus insuring the maintenance of the effect of the screen grid 20s in nullifying the coupling effect between the plate and the grid. A condenser 32 connects the junction of the resistance 31 with the screen grid 20s to the conductor 15, whichmay be grounded, whereby the condenser 32 by-passes any stray radio frequencies.

Inductively related to the primary 21 is a secondary or inductance 41 connected across the terminals of which is connected a variable condenser 42, forming an oscillating circuit, one side.

of which is connected to the grid 40g of a detector or rectifying tube 40, provided with a cathode 400, that is conneced to the other side of the oscillating circuit by conductor 43. The rectifier tube 40 and the rectifying tube 120 hereinafter described may be termed permanent to signify that during the operation of the device the tubes are not removed. It does not signify, however, that the tubes may be removed when the device is not in operation or when that portion of the arrangement in which these tubes are located is not in operation.

The connection of the grid 40g to inductance The plate anode 40p of the detector 40 is con- .7

nected in an output circuit in which is included the primary 47 of a low or audio-frequency transformer, the circuit being connected to and including a suitable uni-directional source of relatively high potential. To this end the circuit is completed substantially as follows: From the plate 40;!) leads a conductor 48.to pole 113 of switch 107 and thence by pole 112 to primary 4'7 of an audio-frequency transformer. In series with conductor 48, and the primary 4'7 is a conductor 51, which leads to a variable tap 16d positioned on the relatively negative side of resistance 16.

The audio-frequency transformer is provided with a suitable iron core 52, and has a secondary 61 forming part of the -input circuit to an audiofrequency amplifying device, here generally indicated as a three-element tube 60, having a heated cathode 60c, and a grid 609 which is connected to one terminal of secondary 61, the other terminal being connected to the cathode 600 in the usual manner.

The plate 60p of the amplifier 60 has impressed upon it a suitable high potential, which is conveniently achieved by connecting the plate through conductor 62 and choke 63 to a point 64 preferably intermediate of the chokes 17 and 18; in commercial practice the potential thus applied to the plate 60p is on the order of 180 volts. A suitable translating device, indicated diagrammatically at 65 and here referred to as aloud speaker, is associated with and connected in parallel with conductor 62, this connection being preferably made through a suitable condenser 66, the other terminal of the device being connected to the relative negative side of the power supply, for example, bus 15. The choke coil 63 serves to prevent audio-frequency currents from reacting on other portions of the circuit through the common source of potential and serves also to smooth out any fluctuations that tend to appear in the potential applied to the plate 60p. Condenser 66 serves to protect the loud speaker against excessive voltages.

The radio amplifying stages associated with the inductance at 101 are adapted to amplify a band of frequencies different from those ampli fied in the stages associated with the inductance 10' and have a detector or rectifying stage, the output of which is arranged to supply the audio stages above described. The first oscillating circuit associated with the inductance 101 is completed by connecting across its terminals a variable condenser 102, one side of this oscillating circuit being connected by a conductor 103 to the grid electrode 100g of a thermionic amplifying tube 100 which is connected in parallel with the condenser 102. The other side of the oscillating circuit is joined by a conductor 104 to the conductor 105 which leads from bus 15 to supply heating current to the cathode element 1000. The circuit for the cathode element 1000 is completed through a conductor 106 and a double throw-switch, shown generally at 107, leading to the battery at 12. This is here accomplished by connecting the conductor 106 to a pole 108 of the switch 107 which has a blade adapted to have contact with a central movable blade 109 having its pole connected to a branch 19!: of the conductor 19 that leads directly to the terminal of battery 12. A third pole has a blade 110 here shown as in conducting relation withthe blade 109, the pole of the blade 110 being connected directly to the bus 19, above described.

The blade 109 being movable is seen in one position to energize the busses 15 and 19, so as to supply heating current to the amplifying stages associated with inductance 10'. when the switch is moved to the other position, namely that in which the blade 109 contacts with that on pole 108, the busses and 106 are energized, so as to supply heating current to the amplifying stages associated with the inductance 101. Where such a switch is employed, the audio stages of amplification which are desired to be common to the two sets of radio-stages, have permanent connections to the source of heating current; hence the cathode element, shown at 60c, is connected across the bus 15 and the branch 19b.

Tube 100, like tube 20, has a screen grid'100s which has potential applied thereto by a con-" ductor 114 leading to a variable tap lite on resistance 16 having a high resistance'1l5 in series therewith. A condenserllfi is-also connected be tween the screen grid and the'conductor 105, in order to block the passage of currents of undesirable frequency as above described.

The inputcircuit of tube 100 which contains inductance 101 is adapted to respond to very high radio frequencies, for example, those of wavelength of the order of 30 or 40 meters. The inductance 101 has accordingly relatively few turns which are so proportioned with reference to condenser 102 as to make this portion of the radio system responsive to the desired band of shortwave frequencies.

The output circuit is connected to the plate anode 100p which comprises inductance 117 and the parallel connected variable condenser 118; the other side of the circuit l17-1l8 is connected by conductor 119 to the relatively high potential tap 16e on resistance 16.

A detector or rectifying tube 120, preferably of similar construction and characteristics to tube 40, has its control grid 1209 connected to be responsive to the energy of circuit 117118, the couplingfor this purpose preferably being capacitive. A condenser 121, preferably variable is interposed between one side of the circuit and the grid 120g, the other side being connected by a similar condenser 122 to the cathode element 1200. The condensers 121 and 122 and the relatively high grid leak resistance 123 serve to insure proper rectifying action by the detector.

The plate anode 120p is connected through another portion of switch 107 to the .common audio-frequency stages. For this purpose, this second portion of switch is similar to the first and has three poles provided with blades 111, 112 and 113 respectively. The pole of blade 111 is connected directly to plate anode 120p, the pole of blade 113 to plate anode 40p of the other rectifying tube 40 by way of conductor48, while the pole-of the central or movable blade 112 is connected with the primary 47, above described.

The two portions of switch 107 above described are preferably mechanically connected, as by a mechanical link 127, so as to move in unison whereby when blade 109 is in contact with blade in the first portion, the blade 112 will be in contact with blade 113 in the second portion, and

vice versa. Thus it is seen that the busses 15 and 19 are energized to supply heating current to the radio and detecting stages associated with inductance 10', the plate anode 40p of such detecting stage is adapted to supply rectified radioenergy into the primary 47, blades 112 and 113 being in contact. Likewise when switch 107 is moved to its other position, blades 108 and 109 are in contact, also blades 111 and 112. In this position, heating current is supplied to the cathode elements 1000 and 1200 while that to cathode elements 200 and 40c is cut oil; also the output of plate anode p is conductivelyoonnected to primary 47, while plate anode 40:) is disconnected therefrom. The audio amplification here employed is thus actuated for either position of switch 107 and the signal picked up made intelligible in the common translating device 65. It will be understood that switch 107 may be modified by adding or omitting blades or parts to adapt it to condition of the circuits it is intended to control, so long as the switch serves as the means for switching from one band of frequencies to another to which the system is intended to be sensitive for the purpose of employing common audiov amplification and translating means.

- The variable condensers 11c, 22 and 42, may if desired be mechanically coupled together in order that the tuning and coupling in the radio stage, may be controllable from a single manual control105 and thereby permit predetermination of the periodicities of the several tuned coupled circuits simultaneously and conjointly. A similar arrangement may be employed in connection with condensers 102 and 118. It is to be understood, however, that these condensers may be individually adjusted, if desired, and that, furthermore, the predetermination of the periodicity of each of the coupled tuned circuits may be otherwise adjusted when desired.

Since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or 120 shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is: 125

1. In a radio-receiving system, in combination, a radio-frequency amplifying means including an electronic-conduction device having an input circuit capable of being tuned throughout a predetermined range of frequencies and an output circuit, a radio-frequency amplifying means having an input circuit capable of being tuned throughout a range of frequencies other than said predetermined range also having an output circuit, permanent rectifying means associated with each 135 of the first said amplifying -means, audio-frequency-responsive translating means adapted to be responsive to a function of the output of said rectifying means, and selection means for connecting said translating means to be responsive to either of said permanent rectifying means.

2. In a radio-receiving system, in combination, a radio-frequency amplifying means including therein an electronic-conduction device having an input circuit capable of being tuned 5 throughout a predetermined range of frequencies and an output circuit, a radio-frequency amplifying means having an input circuit capable of being tuned throughout a range of frequencies other than said predetermined range also having an 15g;

output circuit, permanent rectifying means associated with each of said first named amplifying. means, an audio-frequency responsive translating device adapted to be responsive to a function of the output of said rectifying means, and switch means for connecting selectively said translating device to be responsive to either of said permanent rectifying means.

3. In a radio-receiving system, in combination, a radio-frequency amplifying means including therein an electronic-conduction device having an input circuit capable of being tuned throughout a predetermined range of frequencies and a to said sources said amplifying means which are to be responded to and for simultaneously disconnecting from said sources those amplifying means which are not to be responded to.

4. In a radio-receiving system, in combination, a radio-frequency amplifying means including therein an electronic-conduction device having an input circuit capable of being tuned throughout a predetermined range of frequencies and an output circuit, a radio-frequency amplifying means having an input circuit capable of being tuned throughout a range of frequencies other than said predetermined range also having an output circuit, permanent rectifying means associated with each of said first named amplifying means, 'an audio-frequency-responsive translating device adapted to be responsive to a function of the output of said rectifying means, and switch means for simultaneously disconnecting and deenergizing means to said translating device through the respective permanent rectifying means to be responsive to the rectified output of said other amplifying means.

5. In a radio-receiving system, in combination, an element adapted for collecting electro-magnetic radiation, a radio-frequency amplifying means associated with said element and including an electronic-conductiondevice having an input circuit capable of being tuned throughout a predetermined rang of frequencies and an output circuit, a radio-frequency amplifying means associated with said element and having an input circuit capable of being tuned throughout a range of frequencies other than said predetermined range also having an output circuit, rectifying means associated with each of the first said amplifying means, audio-frequency-responsive translating means adapted-to be responsive to a function of the output of said rectifying means, and means for connecting said translating means to be responsive to the rectified output of either of said amplifying means.

6. In a radio-receiving system, in combination, an element adapted for collecting electro-magnetic radiation, a radio-frequency amplify means associated with said element and including therein an electronic-conduction device having an input circuit capable of being tuned throughout a predetermined range of frequencies and an output circuit, a radio-frequency amplifying means associated with said element and having an input circuit capable of being tuned throughout a range of frequencies other than said predetermined range also having an output circuit, rectifying means associated with each of said first named amplifying means, an audio-frequency responsive translating device adapted to be responsive to a function of the output of said rectifying means, and switch means for connecting selectively said translating device to be responsive to the rectified output of either of said amplifying means.

7. In a radio-receiving system, in combination,

an element adapted for collecting electro-magnetic radiation, a radio-frequency amplifying means associated with said element and including therein an electronic-conduction device having an input circuit capable of being tuned throughout a predetermined range of frequencies and: an output circuit, a radio-frequency amplifying means associated with said element and having an input circuit capable of being tuned throughout a range of frequencies other than said predetermined range also having an output circuit, rectifying means associated with each of said first named amplifying means, an audio-frequency-responsive translating device adapted to be responsive to a function of the output of said rectifying means, and switch means for simultaneously disconnecting and deenergizing one of said amplifying means while connecting said translating device to be responput of said amplifying tube, an amplifying tube and associated elements adapted for receiving short radio waves, a tube adapted for detecting the output of said short-wave tube, an audiofrequency tube adapted for receiving the output of either of said detecting tubes, a translator connected to said audio tube, a single power source, a switch adapted for simultaneously connecting said audio tube to one of said detectors, disconnecting said audio tube from the other of said detectors, for connecting said one detector and its radio-frequency tube to said source, and for disconnecting said other detector and its radio frequency tube from said source.

9. In a device for receiving long or short radio waves, the combination comprising an antenna, short-wave detecting means, long-wave detecting means, a source of power, a translator and a switch vfor connecting said translator and said source to one of said means and for disconnecting said translator and said source from the other of said means.

10. In a device for receiving long or short radio waves, the combination comprising an antenna, short-wave amplifying and detecting means, longwave amplifying and detecting means, a source of power, a translator and a switch for connecting said translator and said source to said first-mentioned means and for disconnecting said translator and said source from said last-mentioned means and vice versa.

11. The combination of a long-wave radio receiver having a' plurality of amplifying stages and a detector stage having plate and cathode circuits, each stage having a thermionic tube permanently associated therewith, a source of current power for supplying the' anodes of said tubes, and a shortwave adapter for said long-wave receiver having a detector tube, an input circuit therefor tunable to the short waves, means for connecting the oathode and anode of said short-wave detector tube removably with the cathode and anode circuits of said long-wave detector tube, whereby also to connect the anode of said short-wave detector tube with said source of high tension direct-current power, and a source of low-tension direct current for heating the cathode of said short-wave detector tube.

EUGENE L. BRESSON. 

